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Tuning of the magnetic properties of intermetallic materials is increasingly gaining interest in the chemistry community. We report on the successful synthesis and magnetic characterizations of the two new quaternary boride series MRh6- nRu nB3 (M = Co, Ni; 1 ≤ n ≤ 5). Powder samples have been synthesized by arc-melting the elements under purified argon in a water-cooled copper crucible. The products were characterized by powder X-ray diffraction through Rietveld refinements as well as EDX measurements. All phases crystallize in the hexagonal Th7Fe3 structure type (space group P63 mc, no. 186, Z = 2). In the Co-based series, the lattice parameters decrease linearly with increasing ruthenium content, whereas in the Ni-based series they remain nearly constant for the Rh-rich side then decrease with increasing Ru content. Significant ferromagnetic interactions are observed for the Co-based series, and they decrease linearly with increasing Ru content with magnetic moments decreasing from 0.74 µB (CoRh5RuB3) to 0.13 µB (CoRhRu5B3) at 5 K and 5 T. Pauli paramagnetism dominates the Ni-based series. [ABSTRACT FROM AUTHOR]

Nb2RuB2 and Ta2RuB2 phases were recently predicted by GGA-VASP structure optimization to crystallize in the Nb2OsB2-type structure. Although the Fe-based (Mo2FeB2 type) and Os-based (Nb2OsB2 type, superstructure variant of Mo2FeB2 type) analogues have been synthesized and characterized successfully, the Ru-based phases remained unknown. Crystal structure prediction of Nb2RuB2 and Ta2RuB2 phases, using an evolutionary algorithm, led to the AlMn2B2-type structure in contrast to the aforementioned optimization; however, phonon calculations showed that the Nb2OsB2-type phases are dynamically more stable than the AlMn2B2-type phases. A slightly modified synthetic strategy finally led to the successful preparation of the predicted phases. The extremely quick arc-melting procedure, under argon atmosphere, not only led to a quantitative amount of the phases but also to single crystals suitable for structure determination. Powder and single-crystal X-ray diffraction as well as EDX analysis of the metal ratio have confirmed the GGA-VASP structure optimization: Nb2RuB2 and Ta2RuB2 compounds indeed crystallize isotypically with Nb2OsB2 structure, a superstructure variant of Mo2FeB2 type, in which B-dumbbells and Peierls-distorted Ru-chains are found. Susceptibility measurements on a Ta2RuB2 single crystal reveal no superconducting transition down to 2 K, even though some features in the band structures of both phases, similar to those reported in superconducting NbRuB, hinted at possible superconductivity. [ABSTRACT FROM AUTHOR]

Ta3Ru5B2, Zr2.86(5)Ru5.14(5)B2, and Hf2.83(2)Ru5.17(2)B2 have been successfully synthesized as polycrystalline powders as well as single crystals and characterized by powder and single- crystal X-ray diffraction and EDX analysis. Furthermore, their electronic structures and bonding characteristics have been analyzed by DFT calculations. The three phases are isotypic and crystallize with a Ti3Co5B2-type structure (space group P4/mbm). Their electronic densities of states, which all possess a large pseudogap at the Fermi level, closely follow the rigid band model. Bonding analyses indicated that Ru-B and Ru-M (M = Zr, Hf, Ta) heteroatomic interactions are mainly responsible for their structural stability and that the homoatomic M-M interactions behave differently when connecting either two tetragonal or two pentagonal Ru prisms at the same distance. [ABSTRACT FROM AUTHOR]

Single crystals and polycrystalline samples of (Nb2- xSc x)4 gNb2 aRu5B2 (1 ≤ x < 2), Nb3- xM xRu5B2 (M = Ti, V; x ≈ 1), and Nb2+ xM1- xRu5B2 (M = Cr, Mn, Fe, Co, Ni; 0 < x ≤ 0.5) were synthesized from the elements and characterized by single-crystal and powder X-ray diffraction as well as energy-dispersive X-ray analysis. These phases are substitutional variants of the recently reported Nb3Ru5B2 phase and crystallize in the Ti3Co5B2-type structure (tetragonal, space group P4/ mbm, no. 127). The structure consists of layers of ruthenium atoms that build trigonal, tetragonal, and pentagonal prisms, in which the other atoms are incorporated. The larger 3d metals, Sc, Ti, and V are found on the larger pentagonal prisms, together with niobium, and also (except for Sc) on the tetragonal prisms. The smaller 3d metals, Cr-Ni, are only found on the tetragonal prisms, but also mix with niobium. DFT calculations on the ternary phase Nb3Ru5B2 suggested that the reason for this site mixing can be found in its electronic structure and the application of the rigid band model proposed a valence electron (VE) range between ca. 58 and 64 for the derived stable phases. All synthesized quaternary phases fit very well within this VE range. [ABSTRACT FROM AUTHOR]

Polycrystalline samples and single crystals of four members of the new complex boride series Ti3−xRu5−yIryB2+x (0 ≤ x ≤ 1 and 1 < y < 3) were synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. The new silvery phases were structurally characterized by powder and single-crystal X-ray diffraction as well as energy- and wavelength-dispersive X-ray spectroscopy analyses. They crystallize with the tetragonal Ti3Co5B2 structure type in space group P4/mbm (No. 127). Tetragonal prisms of Ru/Ir atoms are filled with titanium in the boron-poorest phase (Ti3Ru2.9Ir2.1B2). Gradual substitution of titanium by boron then results in the successive filling of this site by a Ti/B mixture en route to the complete boron occupation, leading to the boron-richest phase (Ti2Ru2.8Ir2.2B3). Furthermore, both ruthenium and iridium share two sites in these structures, but a clear Ru/Ir site preference is found. First-principles density functional theory calculations (Vienna ab initio simulation package) on appropriate structural models (using a supercell approach) have provided more evidence on the stability of the boron-richest and -poorest phases, and the calculated lattice parameters corroborate very well with the experimentally found ones. Linear muffin-tin orbital atomic sphere approximation calculations further supported these findings through crystal orbital Hamilton population bonding analyses, which also show that the Ru/Ir−B and Ru/Ir−Ti heteroatomic interactions are mainly responsible for the structural stability of these compounds. Furthermore, some stable and unstable phases of this complex series could be predicted using the rigid-band model. According to the density of states analyses, all phases should be metallic conductors, as was expected from these metal-rich borides. [ABSTRACT FROM AUTHOR]

The ternary borides Ta3Ru5B2, Zr2.86Ru5.14B2, and Hf2.83Ru5.17B2 are synthesized by arc-melting of stoichiometric mixtures of the elements (Ar, Cu crucibles). [ABSTRACT FROM AUTHOR]

Thequinary members of the complex boride series Sc2FeRu5–xIrxB2were synthesized by arc melting the elementsand characterized by powder and single-crystal X-ray diffraction aswell as metallographic and energy-dispersive X-ray analyses. The useof a 4d/5d mixture allows distinguishing these elements with X-raydiffraction methods, thus enabling the study of site preference andits influence on the magnetic properties. [ABSTRACT FROM AUTHOR]

Ta2OsB2 (I) and TaRuB (II) are prepared by arc-melting of stoichiometric amounts of the elements. [ABSTRACT FROM AUTHOR]

Single crystals of the solid solutions CeRu1-xNixSn (x = 0.12-1) are obtained by melting stoichiometric mixtures of the elements (arc welded Nb ampoules, 1670 K, 5 min; controlled cooling). [ABSTRACT FROM AUTHOR]

Sc2FeRu5-xIrxB2 (x: 1, 2, 3, 4) are prepared by arc melting of the elements several times under Ar (20 s, 40 A). [ABSTRACT FROM AUTHOR]

Polycrystalline samples of the boride series Ti9-xM2+xRu18B8 (M: Cr, Co, Mn, Ni) and single crystals of Ti8Co3Ru18B8 are prepared by arc melting of the elements. [ABSTRACT FROM AUTHOR]